Over the past few years, an experimentally consistent model of chromatin structure has emerged which postulates the presence of regularly repeating subunits joined by short segments of DNA. The elucidation of a subunit structure in chromatin immediately poses the question as to the possible role of this organization in those biological processes in which chromatin participates. In this laboratory, they have been concerned with the possible role of this structure in the transcription of specific viral and cellular genes. We have chosen the globin genes as a model system for the elucidation of the structure of specific genomes in chromatin and the mechanism through which this information is expressed. Coordinately we are examining the integrated viral genome with the ultimate goal of understanding the mechanism of transformation by oncogenic RNA viruses. BIBLIOGRAPHIC REFERENCES: Axel, R., Cedar, H., and Felsenfeld, G. (1975) The structure of the globin genes in chromatin. Biochemistry, 14: 2489-2495. Axel, R. (1975) Cleavage of DNA in nuclei and chromatin with staphylococcal nuclease. Biochemistry, 14: 2921-2925.